Eukaryotic genome is packaged into a highly dynamic chromatin structure, the unit of which is nucleosome, composed of four different core histones octamer wrapped around by 146 by of DNA. The posttranslational modifications namely reversible acetylation, methylation, phosphorylation etc., of the tails of the core histones significantly contribute to the dynamic structure-function organization of chromatin which in turn plays a crucial role in the different DNA-templated phenomenon in the cell. Among these modifications recent focus on histone methylation and its cellular function has gained a broad spectrum of interest. The various disorders where HMTases play a significant role include cancers at the top of the list, followed by cardiovascular diseases, viral pathogenesis as well as multiple sclerosis.